Large storage cabinets used in the construction industry are often formed of steel sheet. Such cabinets typically include opposed side walls, a rear wall, a floor, a ceiling, and one or two doors that are pivotally mounted on the front edges of the side walls to provide access to the cabinet from the front. The floor, walls and ceiling of the cabinet can be formed either from a single sheet of steel that is bent at intersecting edges of these surfaces or from multiple pieces of sheet steel that are welded together. Often, such a cabinet will also include one or more shelves which facilitate the storage of tools and other items. Also, many cabinets have bolsters underlying the floor, and some will include casters beneath the bolsters. The doors of the cabinet are typically formed of a single sheet of steel and, with the exception of narrow finishing flanges around the edges, they are relatively flat. Typical sizes for such a cabinet can range from 40 ft3 to 60 ft3 or even larger. Exemplary storage cabinets include those sold under the name JOBOX® by Delta Consolidated Industries, Jonesboro, Ark. and those sold under the name JOBMASTER® by Knaack Manufacturing, Crystal Lake, Ill.
As noted above, many storage cabinets of the type described above have doors pivotally attached to the front edges of the side walls to alternatively allow and prevent access to the cavity of the cabinet from the front. Generally such cabinets have a vertical support member that is mounted to and extends from the floor to the ceiling. The support member is positioned such that it spans the gap between the free edges of the doors when they are closed. Each door will typically have an engaging member of a latch (such as a hook) attached near its free edge that interacts with a latching mechanism attached to the support member. As an example, one latching mechanism includes horizontally-disposed pins that engage with hooks on the doors and thereby latch the doors in place. The pins are mounted on a vertical rod that is slidably mounted to the rear surface of the support member. The pins can be raised to unlatch the doors via a lever or knob that extends forwardly from the vertical rod through a vertical slot in the support member.
Many cabinets will also include a locking system that enables the doors to be locked in the latched position. One such locking system (illustrated in U.S. Pat. Nos. 4,290,281 and 5,076,078 to Weger, Jr.) includes a “pocket” located in the vertical support member that houses a padlock. The padlock is disposed horizontally within the pocket, with the “key insertion end” of the padlock body being exposed for forward access through the pocket, and the shackle of the padlock extending toward the cavity of the storage cabinet and being restrained by a bracket within the pocket. The body and shackle surround an upright notched member that is attached to and moves vertically with the latching mechanism. When the padlock is locked, the body engages the notch of the notched member, so vertical movement of the latching mechanism is prevented (i.e., the doors of the cabinet are locked and remain locked). When the padlock is unlocked, horizontal movement of the body away from the shackle creates sufficient space for the notched member to become disengaged from the body, and the latching mechanism is free to move vertically to unlatch the doors of the cabinet. This type of locking configuration is particularly desirable for storage cabinets used and left overnight at construction sites, as the pocket protects the lock from being destroyed by someone severing the shackle with a bolt cutter or a similar tool.
One difficulty with the latching and locking mechanisms of current storage cabinets is the inconvenience of opening the cabinet when an operator's hands are full. Even if the cabinet is unlocked and the latching mechanism is free to move, the operator is forced to reach with his hand to grasp and pull the latching lever. If many items are being carried, or if an item being carried is particularly heavy or bulky, the operator may be forced either to set down some or all of his load or to balance the load with one hand and arm in order to unlatch the doors of the cabinet.
Another performance issue of current latching systems presents itself when the operator wishes to close the doors. With the system described above, often the latching mechanism will remain in the unlatched position after unlatching, either simply by friction or through a subassembly designed for this purpose. An operator opens the doors by moving release lever to the unlatched position, at which time both doors would have the opportunity to open. Often, both doors tend to open; this is particularly true if the cabinet is positioned on uneven ground, with the front of the cabinet being lower than the rear of the cabinet. If the operator reaches in to gather items from within the cabinet and has his hands full, closing and latching the doors is difficult, because the latch remains in the unlatched position until actively moved back by the operator. A related problem occurs when the operator wishes to open only one door; with the latching mechanism in the unlatched position, the door that he wishes to remain closed will have a tendency to open unless he actively moves the release lever back to the locking position after opening the door he wishes to open.
Another shortening of the current cabinets is the tendency of the bolsters to fracture when casters are mounted thereunder. The bolsters are typically formed of a single sheet of steel bent into the shape of an open rectangular box. The cabinets are often loaded sufficiently that bolsters of this structure may have inadequate strength to support the load; as a result, the bolsters fail at the mounting locations of the casters.